Love this series! I think this entry is likely the best in the entire series, probably next to the second one.
I’d add a few more things however, more to reflect Cedar’s character progression over the course of the series. Perhaps when they’re in the bathroom, they look into the mirror and see the scratches and bruises they’ve gotten on their arms and such over the course of their journey with Ben? Perhaps they don’t recognise themselves at first? I’d like to add that to space out and seem the conclusion feel more natural, maybe you can add some more scenes where they’re exploring their apartment more before being interrupted by Kane. After being interrupted, maybe they go back to fully moving in. Placing their old things, perhaps you highlight and then transition to exploring some of their possessions and memories that way?
I didn’t see too many grammar or spelling errors, but I did find something that was bothering me.
Mother looked at them silently for a moment, waiting to see if they’d find the answer to their own question. They took their gaze away from the pillar when they realized Mom hadn’t spoken in a while. “It’s just a rock.”
I’d replace ‘mother’ with mom for the sake of consistency and making the paragraph flow better. Other than that, I didn’t see anything that substantially bothered me
I’m looking forward to seeing more of this character, wherever you take them.